Sewing machine attachments



'April 2s, 1964 Filed Feb. l2, 1962 FIG.1.

T. D. AlNSLlE ETAL SEWING MACHINE ATTACHMENTS 2 Sheets-Sheet 1 April 28, 1964 T. D. AlNsLlE ETAL SEWING MACHINE ATTACHMENTS 2 Sheets-Sheet 2 Filed Feb. `12, 1962 FIG- United States Patent O York Filed Feb. 12, 1962, Ser. No. 172,494 1 Claim. (Cl. 112-154) This invention relates to sewing machine attachments, and more particularly to a device which is operative to provide for looseness or slack in certain loops of the stitching produced by the machine.

In the present art of machine sewing, the needle and thread pierce the fabric and pass through it so that the eye of the needle extends beyond the lower face of the cloth. At that time, the hook from the bobbin catches the thread, pulls it down and passes the bobbin thread through the loop in the needle thread, thus engaging the two threads together. The needle then moves upwardly and vertically and draws the bottom or bobbin thread tightly against the lower surface of the fabric, thus forming the stitch.

The sewing thread, during the above-described stitching operation, is under some tension in order to produce a smooth, flat-appearing seam. The tension used in sewing may vary, but it tends to stretch the thread and thus adds to the potential shrinkage of the thread later. If the tension is removed or materially reduced, the machine will not sew well at high speed, nor will the seam have a good appearance on its face.

When a seam is made in the conventional manner as above described, and with the stitching relatively tight, shrinkage of the thread in the seam occurs when the garment is washed, and as a result the fabric of the garment becomes puckered along the steam. It is important in many garments, such as various types of outer garments, that such puckering be prevented since it materially detracts from the appearance of the garment. This is particularly true of garments which are intended to be used with little or no ironing, since puckering causes an unsightly appearance in the sewn areas and may require ironing of the garment to eliminate it. It is therefore one of the objects of the present invention to provide a means and method for sewing by which a certain regulated amount of looseness may be provided in certain loops of the thread, and particularly in those loops adjacent to the lower face of the fabric being sewed, thereby making the thread of the seam extensible and compensating for its possible shrinkage so that after washing of the garment the loops of the seam will be disposed flatly and evenly against the surface of the fabric; the appearance of the seam will be normal and there will be no puckering along the line of the seam.

It is an object of the invention to provide an attachment for producing sewing as above described and which attachment is preferably applicable to a sewing machine of conventional type, and which attachment will be elfective to produce the required looseness or slackness in the loops of the seam to secure the desired effect.

More particularly, the invention contemplates the provision of a reciprocating element and means for inserting such element through each of the lower or bobbin-thread loops and momentarily maintaining the element in each of the loops until the thread take-up has put the proper tension on the thread, and then withdrawing the element from within the loop to leave the required amount of slackness in the loop.

With these and other objects to be hereinafter set forth in View, we have devised the arrangement of parts and steps to be described and more particularly pointed out in the claim appended hereto.

ICC

In the accompanying drawings, wherein an illustrative embodiment of the invention is disclosed,

FIG. 1 is a top plan view of an apparatus constructed according to the invention, with some parts fragmentarily shown to disclose construction;

FIG. 2 is a sectional view, taken substantially on the line 2-2 of FIG. 1, looking in the direction of the arrows;

FIG. 3 is a side elevational view, with a portion in section, of the slidable bar and the pin carried thereby;

FIG. 4 is a sectional View, taken substantially on the line 4-4 of FIG. l, looking in the direction of the arrows;

FIG. 5 shows a line of stitching as produced by conventional sewing machine operation;

FIG. 6 shows a line of stitching as produced by a sewing machine in which the present apparatus is embodied, and

FIG. 7 shows a line of chain stitching as produced by the present apparatus but when a looper instead of a revolving hook type bobbin is used.

In FIG. 5 of the drawing is disclosed a seam or line of stitching as produced in the conventional manner by the usual sewing machine. Therein, the fabric workpiece is indicated at 1; the needle-applied thread at 2, and the bobbin-supplied thread at 3. In this seam, the loops of the threads Z and 3 are drawn taut and snugly against the opposite faces of the fabric. As a result, shrinkage of the thread causes undesirable puckering of the fabric in the vicinity of the seam.

By reference to FIG. 6, the result secured by applicants method and apparatus to be described, will be apparent. By the disposition of a movable element such as a slender rod or pin 4 within each of the loops 5 formed in the bobbin-provided thread 3, substantially as shown at the left in FIG. 6, and maintaining the rod or pin in each loop momentarily-until the thread is tensioned by the take-up of the machine, a regulatable amount of slack or looseness is provided in the thread which forms the loops. This looseness is such as not to be apparent upon visible inspection of the seam, yet it is suicient to compensate for shrinkage of the thread and permit the thread forming the seam, after laundering of the garment, to assume the aspect of the seam shown in FIG. 5 and without causing puckering of the garment in the vicinity of the seam.

The method of stitching can be applied to single needle lock-stitch as shown in FIG. 5, to single thread or double thread chain stitch as shown in FIG. 7, the latter requiring however, the use of a looper instead of a revolving hook type bobbin; in double-needle two-thread chain stitch or any other stitch employing a back thread, or any place where the surface thread comes through to the back of the fabric and to an extent as to permit the loop-engaging rod or pin to restrain the thread from being drawn to a taut position against the rear part of the fabric.

The pin or rod 4 which engages with the loops of the thread as above described, is fitted in and projects from the forward end of a slidable bar 6 constituting a reciprocating member. The rod or pin 4 is removably litted in the forward end of the bar 6 and is maintained in the recess 7 therein by means of a set screw 8. The diameter of the rod or pin 4 determines the amount of bobbin-provided thread held back, the larger the diameter of the pin, the greater will be the amount of bobbin thread to each loop. The rod or pin 4 may have various shapes to secure different results.

The bed of a conventional type of sewing machine to which the device is adapted to be applied, is shown at 9y and the same is provided in its upper surface with a longitudinal groove 10 (FIG. 2) in which the slidable bar 6 is reciprocated. The groove 10 is closed at the top by a plate 11 attached to the top of the bed 9 by means of the screws 12. The bar 6 is thus confined in the groove and is slidably longitudinally therein.

At the end of the bar 6 remote from the pin 4 is a downwardly-extending roller 13, rotatively mounted on a pin 14 threadably extended into the bar 6. A short distance away from the roller 13 is a stud 15, threadably attached to the bar and extending downwardly therefrom. The stud 15 is spaced from the roller 13 and extends downwardly from the bar and parallel to the roller. A slot 34 is provided in the hed 9 to provide for clearance for the stud '15 and the roller 13.

A plunger 16 (FIG. 4) is provided with a transverse opening through it through which the stud 13 passes, said plunger being biased toward the right, as viewed in FIG. 4, by means of a coil spring 33 extending around a reduced-diameter part 18 of the plunger and located in a recess 19 provided in a block 20 fastened by screws 2l to the lower face of the bed 9.

This arrangement is such as to cause the bar 6 to be urged toward the right and to maintain the roller 13 in constant contact with the inclined face 22 of a cam 23, secured by set screws, one of which is shown at 24, to the bobbin-carrying rotative shaft 25 of the sewing machine. The shaft is rotated by the conventional drive means of a sewing machine, in suitable bearings, one of which is indicated at 26. Secured at one end of the shaft 25 is the conventional hook bobbin 32 which acts to cause engagement of the lower thread 3 with the upper thread 2 in the known manner. The sewing machine is, of course, provided with the usual vertically-reciprocated needle, a part of which is shown at 35 in FIG. 7, for providing the upper thread 2 in the sewing in the usual way.

The slotted plate shown at 28 is provided with a guide groove V29 through which the pin 4 is movable, the pin being so positiond that it engages in each of the lower loops as shown in FIGS. 6 and 7 and is momentarily maintained in each of said loops until the thread take-up of the machine has put proper tension on the thread, and the pin is then withdrawn from within the loop to leave the required slackness therein. As the bobbin shaft is rotated, the cam will cause the required reciprocation of the bar 6, causing it to enter and leave the loops as above described.

While we have herein suggested the use of a single loop-engaging pin, it will be apparent that when chainstitching or other types of stitching requiring two needles are used, twoof the loop-engaging pins may be provided.

Thus, while we have herein described a single embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claim.

What we claim is:

In combination with a sewing machine including a horizontal bed having a longitudinal groove therein, a plate having slots over which a piece of fabric to be seamed is passed, adjacent the end of said groove, a reciprocating needle movable vertically through the slots in said plate and through the fabric, said needle being adapted to carry a loop forming upper thread, a hook bobbin adapted to carry a lower loop forming thread engageable with said upper loop forming thread, a rotating shaft carrying said bobbin, and a top plate covering said longitudinal groove; an attachment for providing slack in the loop of a sewing machine produced seam, comprising a rod adapted to be inserted through each loop of one of the threads of the seam between the thread and the fabric while the loops are being formed, momentarily maintaining said rod in the loop until the loop is tensioned, and then withdrawing the rod; a bar having an end opening therein said bar being linearly movable in said groove, one end of said rod seating in said opening, means releasably holding said rod in said opening, said bed having a slot in the bottom thereof intersecting said groove, said groove, bed slot and rotating shaft being in longitudinal and vertical alignment, a stud fixed to the underside of said bar and depending through said bed slot, a roller depending from said bar through said bed slot in parallel relation to said stud, a block having a recess therein secured to the underside of said bed adjacent said stud and between the bed slot and bobbin, a plunger fixed to said stud and having a reduced diameter and piston extending into said recess, the recess facing toward the bed slot, a spring in said recess surrounding said reduced diameter piston biasing said stud, bar, and hence said rod, in a direction away from the thread loops formed by said needle and bobbin, and a carn carried by said rotating shaft engageable with said roller, to bias said bar and hence said rod through each loop formed in the seam in timed relation with each stroke of the needle and rotation of the bobbin.

References Cited in the file of this patent UNITED STATES PATENTS 2,014,687 Lutz Sept. 17, 1935 2,580,724 Bramfitt et al Jan. l, 1952 2,871,486 Kwok Feb. 3, 1959 2,884,882 Donaldson May 5, 1959 2,980,044 Parry Apr. 18, 1961 

